They are quite weak and slow to aim. I feel that P90/AKS makes more damage than minigun. Sounds weird to me.
They are too slow to turn and sector is too narrow -> easy to destroy if enemies coming from more than one direction.
Also make it possible to force AI to use these. Its so stupid that there is free minigun but AI shoots with mossberg next to it. (maybe he knows its more powerful to use mossberg...

)
More power
Faster turning
360 degree firing sector
More attractive for AI
(more price?)
I rather pay 150rp for MG that is useful thatn 70rp for MG that is useless.